Customized patient-specific orthopaedic surgical instrument

ABSTRACT

An orthopaedic surgical instrument includes a customized patient-specific surgical instrument having a body. A cutting guide slot extends through the body. A pair of first arms extends posteriorly from the body. Each arm includes a first customized patient-specific negative contour configured to receive a portion of a first corresponding positive contour of one of a patient&#39;s femoral condyles. A second arm extends proximally from the body. The second arm has a second customized patient-specific negative contour configured to receive a portion of a second corresponding positive contour of an anterior surface of the patient&#39;s femur. A method of performing a surgical procedure is also disclosed.

TECHNICAL FIELD

The present disclosure relates generally to orthopaedic surgicalinstruments and, more particularly, to customized patient-specificorthopaedic surgical instruments.

BACKGROUND

Joint arthroplasty is a well-known surgical procedure by which adiseased and/or damaged natural joint is replaced by a prosthetic joint.For example, in a total knee arthroplasty surgical procedure, apatient's natural knee joint is partially or totally replaced by aprosthetic knee joint or knee prosthesis. A typical knee prosthesisincludes a tibial tray, a femoral component, and a polymer insert orbearing positioned between the tibial tray and the femoral component. Ina hip replacement surgical procedure, a patient's natural acetabulum isreplaced by a prosthetic cup and a patient's natural femoral head ispartially or totally replaced by a prosthetic stem and femoral ball.

To facilitate the replacement of the natural joint with a prosthesis,orthopaedic surgeons use a variety of orthopaedic surgical instrumentssuch as, for example, cutting blocks, drill guides, milling guides, andother surgical instruments. Typically, the orthopaedic surgicalinstruments are reusable and generic with respect to the patient suchthat the same orthopaedic surgical instrument may be used on a number ofdifferent patients during similar orthopaedic surgical procedures.

The orthopaedic surgical instruments may also be customized to aspecific patient. Such “customized patient-specific orthopaedic surgicalinstruments” are single-use surgical tools for use by a surgeon inperforming an orthopaedic surgical procedure that is intended, andconfigured, for use on a particular patient. It should be appreciatedthat these instruments are distinct from standard, non-patient-specificorthopaedic surgical instruments that are intended for use on a varietyof different patients. These customized patient-specific orthopaedicsurgical instruments are distinct from orthopaedic prostheses, whetherpatient-specific or generic, which are surgically implanted in the bodyof the patient. Rather, customized patient-specific orthopaedic surgicalinstruments are used by an orthopaedic surgeon to assist in theimplantation of orthopaedic prostheses.

SUMMARY

According to an aspect of the disclosure, an orthopaedic surgicalinstrument includes a customized patient-specific surgical instrumenthaving a body. A cutting guide slot extends through the body. A pair offirst arms extends posteriorly from the body. Each arm includes a firstcustomized patient-specific negative contour configured to receive aportion of a first corresponding positive contour of one of a patient'sfemoral condyles. A second arm extends proximally from the body. Thesecond arm has a second customized patient-specific negative contourconfigured to receive a portion of a second corresponding positivecontour of an anterior surface of the patient's femur. An alignment slotextends through the body and the proximally extending arm and ispositioned to align with a deepest portion of a trochlear groove of thepatient's femur when the customized patient-specific surgical instrumentis positioned on the patient's femur.

In some embodiments, the alignment slot may extend transverse to thecutting guide slot.

In some embodiments, the body may have a planar distal surface and aplanar proximal surface. The alignment slot may include an openingextending through the distal surface and an opening extending throughthe proximal surface.

In some embodiments, the second arm may include a trunk extending fromthe body and a flange attached to a proximal end of the trunk. Theflange may include a portion of the second customized patient-specificnegative contour. The trunk may include an anterior surface and aposterior surface. The alignment slot may include an opening extendingthrough the anterior surface and an opening extending through theposterior surface. The opening extending through the anterior surfaceand the opening extending through the posterior surface may be curved.

In some embodiments, the customized patient-specific surgical instrumentmay include a boss attached to, and extending from, the body to a freeend spaced apart from the body. The boss may include an opening that isdefined in its free end. A guide hole may extend through the boss.

According to another aspect of the disclosure, an orthopaedic surgicalinstrument includes a customized patient-specific surgical instrumenthaving a body. A cutting guide slot may extend through the body. A pairof first arms may extend posteriorly from the body. Each arm may includea first customized patient-specific negative contour configured toreceive a portion of a first corresponding positive contour of one of apatient's femoral condyles. An alignment slot may extend through thebody transverse to the cutting guide slot and is positioned to alignwith a deepest portion of a trochlear groove of the patient's femur whenthe customized patient-specific surgical instrument is positioned on thepatient's femur.

In some embodiments, the body may have a planar distal surface and aplanar proximal surface. The alignment slot may include an openingextending through the distal surface and an opening extending throughthe proximal surface.

In some embodiments, the customized patient-specific surgical instrumentmay include a boss attached to, and extending from, the body to a freeend spaced apart from the body. The boss may include an opening that isdefined in its free end. A guide hole may extend through the boss.

In some embodiments, a second arm may extend proximally from the body.The second arm may include a trunk extending from the body and a flangeattached to a proximal end of the trunk. The second arm may have asecond customized patient-specific negative contour configured toreceive a portion of a second corresponding positive contour of ananterior surface of the patient's femur. The flange may include aportion of the second customized patient-specific negative contour. Thetrunk may include an anterior surface and a posterior surface. Thealignment slot may include an opening extending through the anteriorsurface and an opening extending through the posterior surface. Theopening extending through the anterior surface and the opening extendingthrough the posterior surface may be curved.

According to yet another aspect of the disclosure, a method ofperforming an orthopaedic surgical procedure includes placing a visualmarking on a surface defining a deepest portion of a trochlear groove ofa patient's femur. The method also includes placing a customizedpatient-specific surgical instrument on the patient's femur. The methodalso includes aligning an alignment slot extending through thecustomized patient-specific surgical instrument with the visual markingon the surface of the patient's femur to position the customizedpatient-specific surgical instrument on the patient's femur.

In some embodiments, the method may include aligning an alignment slotextending through a body of the customized patient-specific surgicalinstrument with the visual marking.

In some embodiments, the method may include aligning an alignment slotextending through an arm of the customized patient-specific surgicalinstrument with the visual marking.

BRIEF DESCRIPTION OF THE DRAWINGS

The detailed description particularly refers to the following figures,in which:

FIG. 1 is a perspective view of a customized patient-specific surgicalinstrument;

FIG. 2 is a bottom perspective view of the customized patient-specificsurgical instrument shown in FIG. 1;

FIG. 3 is a rear elevation view of the customized patient-specificsurgical instrument shown in FIG. 1;

FIG. 4 is another bottom perspective view of the customizedpatient-specific surgical instrument shown in FIG. 1;

FIG. 5 is a top plan view of the customized patient-specific surgicalinstrument shown in FIG. 1;

FIG. 6 is a front elevation view of the customized patient-specificsurgical instrument shown in FIG. 1;

FIG. 7 is a perspective view of distal end of a patient's femur;

FIG. 8 is a perspective view of the customized patient-specific surgicalinstrument of FIG. 1 positioned on the distal end of the patient's femurof FIG. 7; and

FIG. 9 is an elevation view of the customized patient-specific surgicalinstrument of FIG. 1 positioned on the distal end of the patient's femurof FIG. 7.

DETAILED DESCRIPTION OF THE DRAWINGS

While the concepts of the present disclosure are susceptible to variousmodifications and alternative forms, specific exemplary embodimentsthereof have been shown by way of example in the drawings and willherein be described in detail. It should be understood, however, thatthere is no intent to limit the concepts of the present disclosure tothe particular forms disclosed, but on the contrary, the intention is tocover all modifications, equivalents, and alternatives falling withinthe spirit and scope of the invention as defined by the appended claims.

Terms representing anatomical references, such as anterior, posterior,medial, lateral, superior, inferior, etcetera, may be used throughoutthe specification in reference to the orthopaedic implants and surgicalinstruments described herein as well as in reference to the patient'snatural anatomy. Such terms have well-understood meanings in both thestudy of anatomy and the field of orthopaedics. Use of such anatomicalreference terms in the written description and claims is intended to beconsistent with their well-understood meanings unless noted otherwise.

Referring now to FIG. 1, an orthopaedic surgical instrument 10 is shown.The instrument 10 is illustratively a customized patient-specificorthopaedic surgical instrument. What is meant herein by the term“customized patient-specific orthopaedic surgical instrument” is asurgical tool for use by a surgeon in performing an orthopaedic surgicalprocedure that is intended, and configured, for use on a particularpatient. As such, it should be appreciated that, as used herein, theterm “customized patient-specific orthopaedic surgical instrument” isdistinct from standard, non-patient-specific orthopaedic surgicalinstruments (i.e., “patient-universal instruments” such aspatient-universal cutting blocks) that are intended for use on a varietyof different patients and were not fabricated or customized to anyparticular patient. Additionally, it should be appreciated that, as usedherein, the term “customized patient-specific orthopaedic surgicalinstrument” is distinct from orthopaedic prostheses or implants, whetherpatient-specific or generic, which are surgically implanted in the bodyof the patient. Rather, an orthopaedic surgeon uses customizedpatient-specific orthopaedic surgical instruments to assist in theimplantation of orthopaedic prostheses. Examples of “customizedpatient-specific orthopaedic surgical instruments” include customizedpatient-specific drill/pin guides, customized patient-specific tibialcutting blocks, customized patient-specific femoral cutting blocks, andcustomized patient-specific alignment guides.

The customized patient-specific orthopaedic surgical instrument is afemoral cutting guide block 12 in the illustrative embodiment. Theanterior contact surfaces and the distal contact surfaces of the cuttingblock 12 facilitate securing the cutting block 12 on the patient'sfemur. As described in greater detail below, the surgical instrument 10is configured to be coupled to the patient's femur in a uniquepre-determined location and orientation on the patient's condyles and ananterior portion of the femur extending proximally from the condyles.The cutting block 12 contact regions are configured to couple to thepatient's femur in a unique pre-determined location and orientation sothat an alignment slot extending through the cutting block 12 is alignedwith the deepest portion of the trochlear groove. In the illustrativeembodiment, the structure of the cutting block 12 has been contoured toreduce its size relative to conventional cutting blocks and avoidcontact with undesirable regions of the patient's bone.

The femoral cutting block 12 includes a base plate 20 and a number ofsurgical tool guide bodies 22 that are attached to, and extend outwardlyfrom, the base plate 20. In the illustrative embodiment, the femoralcutting block 12 is a single monolithic component formed from a metallicmaterial such as, for example, stainless steel. In that way, the baseplate 20 and the guide bodies 22 form a single monolithic metallicblock. The femoral cutting block 12 is formed by, for example, DirectMetal Laser Sintering (DMLS), also known as Selective Laser Sintering(SLS), which is a form of additive manufacturing technology. In DMLS,the femoral cutting block 12 is formed in a layer-by-layer fashion usinglaser sintering in which light fuses metallic powder, forming themetallic structures that define the femoral cutting block 12. It shouldbe appreciated that other forms of additive manufacturing technologysuch as, for example, optical fabrication, photo-solidification, orresin printing may be used to fabricate the femoral cutting block 12.

The base plate 20 includes a pair of arms 24, 26 that are configured toengage the distal end 18 of the patient's femur 16 (see FIG. 7). Thearms 24, 26 are spaced apart from each other such that a notch 28 isdefined between the inner edges of the arms 24, 26. The notch 28 issized and shaped to correspond to the natural intercondylar notch 30 ofthe patient's femur 16, which is defined between the natural condyles32, 34 of the patient's femur 16 (see FIG. 7).

Each of the arms 24, 26 has a bone-contacting or bone-facing surface 36(shown in FIG. 2) that engages one of the natural condyles 32, 34. Inthe illustrative embodiment, each bone-facing surface 36 includes anumber of negative contours 38 that are configured to receive a portionof the natural condyles 32, 34. Each contour 38 has a unique set ofridges 40 and depressions 42 that are shaped to engage a correspondingunique set of depressions 44 and ridges 46 of the natural femoralcondyles 32, 34 (see FIG. 7). Each of the arms 24, 26 also includes anouter surface 48 that is positioned opposite its correspondingbone-facing surface 36. In the illustrative embodiment, each outersurface 48 is substantially smooth. As used herein, the term“substantially” should be understood to refer to the normal tolerancescreated by manufacturing variation and other design criteria. As such, a“substantially smooth surface” is one that is smooth within the normaltolerances created or permitted by manufacturing variation and otherdesign criteria.

The base plate 20 also includes a proximally extending arm 50 that isconfigured to engage the distal end 18 of the patient's femur 16. Theproximally extending arm 50 includes a trunk 86 and a flange 88extending proximally from the trunk 86. The trunk 86 includes a base 92having first width 94 between a pair of edges 66, 68. The trunk 86extends proximally and narrows to a point 78 that has a width 130 thatis less than the width 94. From the point 78, the trunk 86 flaresoutward to an end 132 having a width 134 that is greater than the width130 and less than the width 94. From the point 78 to the end 132, thetrunk 86 curves laterally to mimic the curve of the trochlear groove166. The trunk 86 is generally concave such that the point 78 extendsanteriorly of the base 92 and the end 132. The trunk 86 also includesconvex and concave portions to receive corresponding concave and convexportions of the patient's femur 16.

The trunk 86 of the proximally extending arm 50 includes a bone-facingsurface 52 (shown in FIG. 2) that includes a number of negative contours54 that are configured to receive a portion of the patient's femur 16.The bone-facing surface 52 extends across the trunk 86 from the base 92to the end 132. The contour 54 of the trunk 86 has a unique set ofridges 56 and depressions 58 that are shaped to engage a correspondingunique set of depressions 60 and ridges 62 of the patient's femur 16.The proximally extending arm 50 also includes an outer surface 64 thatis positioned opposite the bone-facing surface 52. In the illustrativeembodiment, the outer surface 64 is substantially smooth.

The trunk 86 is configured to curve with the trochlear groove 166 of thepatient's femur 16. As illustrated in FIG. 7, the trochlear groove 166extends between the natural femoral condyles 32, 34 and ends at ananterior surface 168 of the femur 16, which begins at an end of thenatural femoral condyles 32, 34. That is, the natural femoral condyles32, 34 curve into the anterior surface 168. The trochlear groove 166also curves laterally between the natural femoral condyles 32, 34. Thetrunk 86 is configured to follow the path of the trochlear groove 166 sothat the flange 88 engages the anterior surface 168 of the patient'sfemur 16.

The flange 88 extends proximally from the trunk 86 and includes a pairof arms 136 that extend medially and laterally from the trunk 86. Theposterior edges 66, 68 extend along the trunk 86 and flange 88. As aresult, each of the edges 66, 68 includes convex and concave portions toreceive corresponding concave and convex portions of the patient's femur16. The edges 66, 68 extend around the arms 136 of the flange and meetat a posterior tip 69 that is sized and shaped to be positioned on theanterior surface 168 of the patient's femur 16. The flange 88 includes abone-facing surface 96 that includes a number of negative contours 98that are configured to receive a portion of the anterior surface 168 ofthe patient's femur 16. The contour 98 of the flange 88 has a unique setof ridges 70 and depressions 72 that are shaped to engage acorresponding unique set of depressions 74 and ridges 76 of the anteriorsurface 168 of the patient's femur 16. The negative contours 38, 54, 98of the base plate 20 permit the cutting block 12 (and hence the toolguide bodies) to be positioned on the patient's femur 16 in a uniquepre-determined location and orientation.

In the illustrative embodiment, the base plate 20 of the cutting block12 has a low-profile to reduce the size of the incision and reduce theamount of bone displacement needed to position the cutting block 12. Thelow-profile has been customized for block 12 by minimizing thethicknesses of the arms 24, 26 and the proximally extending arm 50. Athickness 82 is defined between the outer surface 48 and the bone-facingsurface 36 of each arm. To minimize the thickness 82, the outer surface48 of each arm is convexly curved to follow the concave curvature of thebone-facing surface 36. Similarly, a thickness 84 is defined between theouter surface 64 and the bone-facing surface 52 of the proximallyextending arm 50, and the outer surface 64 of the arm 50 is shaped tofollow the geometry of the bone-facing surface 52 to minimize thethickness 84.

Each of the surgical tool guide bodies 22 of the cutting block 12 isattached to and extends outwardly from the outer surfaces 48, 64 of thearms 24, 26 and the proximally extending arm 50 to a free end 90 that isspaced apart from the base plate 20. In the illustrative embodiment, theguide bodies 22 include an anterior guide body 100 that extendsanteriorly from the anterior ends of the arms 24, 26 and the proximallyextending arm 50 to its free end 102. The anterior guide body 100includes a distal flange 104 and a pair of bosses 106, 108 that extendproximally from the flange 104.

The distal flange 104 of the anterior guide body 100 includes anelongated opening 110 that is defined in the free end 102 and a numberof inner walls 112 that extend inwardly from the opening 110. As shownin FIG. 3, the inner walls 112 extend to another opening 114 that isdefined in the bone-facing surface 52. The opening 114 extends throughthe contour 54 of the base plate 20 such that the opening 114 is definedby the edges 66, 68 of the bone-facing surface 52, which follow acurved, irregular path that matches the shape of the patient's femur 16in that region. The opening 114 cooperates with the inner walls 112 andthe elongated opening 110 to define the guide slot 98, which is sizedand shaped to guide a surgical tool such as, for example, a cuttingblade, into engagement with the patient's bone. As described above, thecutting guide slot 98 is positioned to guide a customized,patient-specific resection of the distal end 18 of the patient's femur16. Because the edge 66 follows the shape of the patient's femur 16 andthe posterior tip of the edge 66 extends into the patient's trochleargroove, the cutting guide slot 98 provides support for the cutting bladein close proximity to the region under resection.

As shown in FIG. 1, each of the bosses 106, 108 extend from a proximalsurface 116 of the distal flange 104 to a curved proximal end 118. Itshould be appreciated that in other embodiments one or both of thebosses 106, 108 may be spaced apart from the distal flange 104, therebyforming separate guide bodies. An opening 120 is defined in the free end102 of each of the bosses 106, 108 adjacent to the proximal end 118. Aninner wall 122 extends inwardly from the opening 120. As shown in FIG.4, each inner wall 122 extends to another opening 124 to define a guideslot 126 extending through the cutting block 12. In the illustrativeembodiment, each guide slot 126 is a drill guide and fixation pin guidehole, which is sized and shaped to guide a surgical drill to prepare thepatient's bone to receive a fixation pin to couple the block 12 to thebone.

The guide bodies 22 include a pair of posterior guide bosses 140, whichare attached to, and extend distally from, the outer surfaces 48 of thearms 24, 26, respectively. Each posterior guide boss 140 includes aguide slot 142 that is sized and shaped to guide a surgical drill and afixation pin into engagement with the patient's bone to couple the block12 to the bone. Each guide boss 140 includes a post 144 that extendsfrom a base 146 attached to the outer surface 48 of one of the arms 24,26 to a free end 148 that is spaced apart from the outer surface 48.

An opening 154 is defined in the free end 148 of each boss 140. An innerwall 178 extends inwardly from the opening 154 to another opening 158(shown in FIG. 2) that is defined in a bone-facing surface 36 of one ofthe arms 24, 26. The openings 154, 158 and the inner wall 178 cooperateto define the guide slot 142. As described above, each guide slot 142 isa drill guide and fixation pin guide hole, which is sized and shaped toguide a surgical drill or self-drilling fixation pin to prepare thepatient's bone to receive a fixation pin to couple to the block 12 tothe bone.

Referring to FIGS. 5-6, the base plate 20 includes an alignment slot 200positioned to align with a deepest portion of the patient's naturaltrochlear groove 166. The distal flange 104 has a planar distal surface202 and a planar proximal surface 204 (shown in FIG. 4). A distal end210 of the alignment slot 200 is defined by inner walls 208 extendingbetween an opening 206 in the distal surface 202 and an opening in theinner walls 112 of the elongated opening 110. The distal end 212 of thealignment slot 200 is also defined by inner walls 230 extending betweenan opening in the inner walls 112 of the elongated opening 110 and anopening 212 in the proximal surface 204. The distal end 210 of thealignment slot 200 extends transverse to the cutting guide slot 98.

The bone-facing surface 52 of the trunk 86 of the proximally extendingarm 50 forms a posterior surface 214 of the trunk 86, and the outersurface 64 forms an anterior surface 216 (shown in FIG. 1) of the trunk86. A proximal end 220 of the alignment slot 200 is defined by innerwalls 218 extending between an opening 222 in the posterior surface 214and an opening 224 in the anterior surface 216. The proximal end 220 ofthe alignment slot 200 extends transverse to the cutting guide slot 98.In the illustrative embodiment, the proximal end 220 of the alignmentslot 200 is curved both laterally and in a concave shape to match acontour of the trunk 86 and the deepest portion of the patient's naturaltrochlear groove 166. The distal end 210 and the proximal end 220 of thealignment slot 200 extend from one another to form a continuousalignment slot 200 that is transverse to the cutting guide slot 98.

Prior to surgery, a three-dimensional model of the patient's femur 16 isdeveloped based on scans of the patient's femur 16. The scans mayinclude a magnetic resonance image, a computed tomography image, aplurality of x-ray images, or the like. The cutting block 12 ismanufactured to include negative contours that match the positivecontours of the three-dimensional model. Additionally the alignment slot200 is formed in the cutting block 12 to match the position of thedeepest portion of the patient's natural trochlear groove 166. Creatingthe cutting block 12 based on the three-dimensional model facilitatesensuring a correct alignment of the cutting block 12 on the patient'sfemur 16.

Referring now to FIG. 7, during use, a surgeon prepares the patient'sfemur 16 by placing a visual indicator 250 on the deepest portion of thepatient's natural trochlear groove 166. In the illustrative embodiment,the visual indicator 250 is a line drawn on the deepest portion of thepatient's natural trochlear groove 166. The cutting block 12 is thenpositioned on a distal end 18 of the patient's femur 16 so that theunique set of ridges 40 and depressions 42 engage the correspondingunique set of depressions 44 and ridges 46 of the natural condyles 32,34 and the unique set of ridges 56 and depressions 58 engage thecorresponding unique set of depressions 60 and ridges 62 of an anteriorside 254 of the patient's femur 16. The unique set of ridges 70 anddepressions 72 of the flange 88 are also positioned to engage thecorresponding unique set of depressions 74 and ridges 76 of the anteriorsurface 168 of the patient's femur 16.

The surgeon verifies the alignment of the cutting block 12 on the femur16 by aligning the visual indicator 250 with the alignment slot 200. Asillustrated in FIG. 8, the proximal end 220 of the alignment slot 200 isaligned with a portion of the visual indicator 250 that extends alongthe anterior side 254 of the patient's femur. As illustrated in FIG. 9,the distal end 210 of the alignment slot 200 is aligned with a portionof the visual indicator 250 that extends along the distal end 18 of thepatient's femur 16 and extends between the natural condyles 32, 34.

The surgeon can then position a fixation pin in each of the guide slots126 and 142 to secure the cutting block 12 to the patient's femur. Adistal resection is then performed on the distal end 18 of the patient'sfemur 16 by advancing a surgical saw through the guide slot 98. In someembodiments, the fixation pins inserted through the guide slots 142 maybe removed before the distal resection of the distal end 18 of thepatient's femur 16 so that the fixation pins do not interfere with thesurgical saw.

While the disclosure has been illustrated and described in detail in thedrawings and foregoing description, such an illustration and descriptionis to be considered as exemplary and not restrictive in character, itbeing understood that only illustrative embodiments have been shown anddescribed and that all changes and modifications that come within thespirit of the disclosure are desired to be protected.

There are a plurality of advantages of the present disclosure arisingfrom the various features of the devices and assemblies describedherein. It will be noted that alternative embodiments of the devices andassemblies of the present disclosure may not include all of the featuresdescribed yet still benefit from at least some of the advantages of suchfeatures. Those of ordinary skill in the art may readily devise theirown implementations of the devices and assemblies that incorporate oneor more of the features of the present invention and fall within thespirit and scope of the present disclosure as defined by the appendedclaims.

The invention claimed is:
 1. An orthopaedic surgical instrument,comprising: a customized patient-specific surgical instrumentcomprising: a body having a planar distal surface and a planar proximalsurface, a cutting guide slot extending through the body, a pair offirst arms extending posteriorly from the body, each arm including afirst customized patient-specific negative contour configured to receivea portion of a first corresponding positive contour of one of apatient's femoral condyles, a second arm extending proximally from thebody, the second arm having a second customized patient-specificnegative contour configured to receive a portion of a secondcorresponding positive contour of an anterior surface of the patient'sfemur, and an alignment slot extending through the body and theproximally extending arm and positioned to align with a deepest portionof a trochlear groove of the patient's femur when the customizedpatient-specific surgical instrument is positioned on the patient'sfemur wherein (i) the alignment slot includes a slot portion extendingthrough the body transverse to the cutting guide slot, and (ii) the slotportion includes a first opening extending traverse to the cutting guideslot through the planar distal surface and a second opening aligned withthe first opening and extending traverse to the cutting guide slotthrough the planar proximal surface.
 2. The orthopaedic surgicalinstrument of claim 1, wherein the second arm includes a trunk extendingfrom the body and a flange attached to a proximal end of the trunk,wherein the flange includes a portion of the second customizedpatient-specific negative contour.
 3. The orthopaedic surgicalinstrument of claim 2, wherein the trunk includes an anterior surfaceand a posterior surface, wherein the alignment slot includes an openingextending through the anterior surface and an opening extending throughthe posterior surface.
 4. The orthopaedic surgical instrument of claim3, wherein the opening extending through the anterior surface and theopening extending through the posterior surface are curved.
 5. Theorthopaedic surgical instrument of claim 1, wherein the customizedpatient-specific surgical instrument includes a boss attached to, andextending from, the body to a free end spaced apart from the body, theboss including an opening that is defined in its free end.
 6. Theorthopaedic surgical instrument of claim 5, including a guide holeextending through the boss.